Switch stand



Nov. 13, 1951 A. F. ANDERSEN 2,575,037

SWITCH STAND Filed Dec. 22, 1945 5 sheeds sheet l I r 29 N m U L INVENTOR. A4 FREQ F. A NDE/PSE/V A TTOIQNEYS Nov. 13, 1951 A. F. ANDERSEN 2,575,037

' SWITCH STAND Filed Dec. 22, 1945 I 5 Sheets-Sheet 2 INVENTOR. ALF/8E0 RA/VDEPSEN BY mpumuzwk A T TURN/5Y5 Nov. 13, 1951 A. F. ANDERSEN 2,575,037

SWITCH STAND Filed Dec. 22, 1945 5 Sheets-Sheet 5 P INVENTQR.

BY M mm Loam A 7' T0142 NEYS 1mm HANDL RS/5N Nov. 13, 1951 Q A. F. ANDERSEN 2,575,037

SWITCH STAND I INVENTOR.

Qk ALFPED F? A NDE'QSE/V.

A] TTOIQNEYS Nov. 13, 1951 A. F. ANDERSEN SWITCH STAND 5 Sheets-Sheet 5 Filed Dec. 22, 1945 N Z mp MM N A S! D M 48 A TTOQNEYS Patented Nov. 13, 1951 swrrori STAND Alfred F. Andersen. Danbury, Conn., assignor to American BrakeShoe Company, New York, N. Y., a corporation of Pelaware Application December 252: media No. 636,620

The invention relates to switchstands for manuticularly to switchstands of the automatic type permitting operation by a locomotive or car running through the switch.

General objects of the invention are to provide an automatic stand having increased instability in dead center position to prevent sticking; to relieve the spindle bearings from spring pressure during automatic operation; to decrease friction 14 Claims. (01. 246-411) I ally operating railroad switches and more parand wear; to minimize machining; to provide for easier assembly and disassembly in field and shop; and generally to provide a better switch stand at lower cost.

According to a preierredform of the invention, the switchstand comprises a separable casing having a vertical spindle journaled therein carrying the target shaft and crank for the connecting rod operating the switch; The spindle includes an off-center open box acting as a crank. Passing through this box is ahorizontally disposed links, a spring base and a thrust bushing, which latter are seated in suitable recesses in the case. The spring basehasa non-circular bore enclos- 2 v to be characteristic of this invention will be particularly pointed out in the claims appended hereto, the invention itself, as to its objectsan'd advantages, and the manner in which it may be carried out, may be better understood by referring'to the following description taken in con.-

nection with the accompanying drawings forming a part hereof, in which:

- v Fig. 1 is a vertical elevation of a switchstand according to the invention with hand lever in one thrown position and showing other thrown position in dot-and-dash lines;

2 against the stock rail nearest the switchstand;

ing a slidable crosshead to which is pivoted a rear link. A special pivot link to remove thrust from the spindle bearings is mounted within the thrust bushing for limited lateral movement and an H-shaped intermediate link is pivoted to both pivot link and rear link. Th H-shaped intermediate link is journaledin a spindle block which slides in the spindle box. A single helical spring surrounds the spring base and acts between it and a spring cap secured to said crosshead. The spring base has a bore in line with the crosshead bore separated by a wall through which an adjusting bolt passes for adjusting the expansion of the spring. A built-in wrench serves to lock this-nut, which wrench is in turn locked in position by engagement with the hand leverwhich is bolted to the spring base. e

For manual operation, the coaction of the horizontal crank and spindle crank operates to turn the spindle to throw the switch during which operation the angular relationship between the links of the horizontal crank assembly may not substantially change. For automatic operation, the horizontal crank does not rotate but the forced rotation of the spindle box causes the angu larly related assembly of links to straighten out against the tension of the spring which'throws operated; and

Fig. 3 is a vertical section through the stand with parts in the same position as shown in Fig. 2; Fig. 4 is a horizontal section similar to Fig. 2 but illustrating. the position of the switchstand when manually thrown'to the position where it crank assembly made up of pivotallyconnected places the switchpoints against the stock rail re-. mote from the switchstand; i

Fig. 5 is a horizontal section similar to Fig. 4, but showing the switchstand in dead center position, mid-way through an automatic operation; Fig. 6 is a vertical section illustrating the midposition of the switchstand when manuallyv operated; 1 Fig. 7 is a horizontal section illustrating the mid-position of the switchstand when manually Fig. 8 is a detail of the crank shaft assembly, with the several links in alignment.

In the following description and in the claims, various details will be identified by specific names for convenience, but they are intended to be as generic in their application as the art will permit. Like referencecharacters denote like parts in the several figures of the drawings.

f In the drawings accompanying and forming part of this specification, certain specific disclosure of the invention is made for purposes of explanation, but it will be understood that the details may be modified in various respects without departure from the broad aspect of the invention. I

Referring now to the drawings and more par;- ticularly to Fig. 1, the switchstand is indicated by ID- and is shown resting on ties H. The switchstand supports a crank I3 pivoted to a connecting rod 14 by pin 15, the connecting rod. ex-i tending to the switchpoints of a railway switch (not shown), as will be understood by those skilled in the art. 'The hand lever" I2 is shown disposed upon simple supporting rests I! but it will be understood that, instead of the rests ll, latching devices may be used for positively locking the handle l2 down in either or both horizontal thrown positions switchstand III has target shaft I6 for supporting a target (not shown), as will be understood. I

Referring now also to Figs. 2-8, the switchstand It comprises a separable case having a lower section 20 and an upper section 2| of generally cylindrical construction and separately connected by bolts l9 at the four corners thereof, bolt holes being indicated by 22. The lower section 28 of the case has angular offsets 33 (Figs. 1 and 2) connected to base flanges '23 hay-'- ing spike holes 29 through which spikes are passed to affix the switchstand to the ties H. Suitable vertical gussets or webs connect the case and base flanges 23 for strength.

The ends of the cylindrical casing are closed by end walls havingrecesses 25 and 26 for the crank assembly described hereinafter. The upper case section "2i has a bearing 21 and the lower case section 20 has "a bearing 28 for the vertical spindle 33.

The spindle 33 '(Fig. 3') includes the target shaft t6 and journals 35 and 3B which'have bearing relationship with bearings '21 and 28 respectively. The journals 35, 36 are connected by sweeping arms forming an open, ofi-center box 31. The spindle 33 supports hub 38 in which is adjustably threaded the crank arm 13 which operates the connecting rod I4 for throwing the switch.

The horizontal crank shaft assembly comprises a thrust bushing '41 at oneend and a spring base 42 at the other end; supported therein (Fig. 8) is an articulated arrangement including pivot link 43, intermediate link 44, rear link 45 and 'crosshe'ad 46. Bolts 47 connect hand lever l-2 to spring base 42 for operating the crank assembly, the hand lever seating in groove 48 in the end of spring base 42.

The thrust bushing 41 has 'a positioning flange 50 and seats in the recess '25; it has a conical socket at the bottom of which is a recess seating a ball 39. 'Disposed within conical-socket 51 is pivot link '43 having a recess 40 which fits over ball "52 so that the pivot'link 43 "has both rotative movement and a limited pivotal movementin an directions within thrust bushing 4|.

Intermediate link 44 has two recesses making it H-shaped. Its outer surface is cylindrical so 'as "to rotate within spindle flolo'ck '51 which has a snug sliding fit within flat-"sided opening '59 of spindle box 31. Rearf'lin'k .45 is pivoted to inter-mediate link 44 and to the crosshead 4B which in the shape oi. a strap.

P'ivot pins '52, 53 and 54, whose axes are parallel, pivot the members 43, 4'4, 45 and 46 together as indicated, locking pins indicated in general by 49 being provided to hold the pivot pins in proper axial position. Pivot .pins '52, 53 are long enough (Fig. 8-) to. confine spindle block 5'1 on 'H-shape intermediate link 44.

An annular spring cap 58 supports helical Spring BI and has recesses 'for the lugs 60 of crosshead 46. Crosshead 4.6 slides axially within bore 55 in spring base 42. lBore 555 is of rectangular cross section and .crosshead 46 .flts thereinsomewhatloosely but closely enough .to .permit no substantial .relative rotation between these :parts while permitting relative axial movement.

The spring -61 seats also against aiiange 55 on spring base 42. Spring base 42 has a reduced hub portion-63 which loosely ;journaled in case hearing.

a An adjusting bolt 64 passes through an opening in-crosshead 46 and an opening in a wall 68 in thesspringbase 42, and a nut 61 .on bolt -64 adjusts the outermost mosition whichspringcap .58 can move with respectto spring base 42. A

built-in socket wrench 65 used for rotating nut 67, this wrench having a square boss 66 which fits into a square hole in hand lever I2.

Thus, when hand lever I2 is bolted to hub 63 by bolts 41, it looks wrench 65 and nut 61 in position. Bolt 64 is kept from turning by engagement of its head between the legs of strap-shaped crosshead 46 as shown in Fig. 7. When it is desired to adjust nut 61, bolts 41 are removed permitting hand lever l2 to be used as a wrench for turning built-in wrench 65.

-Spindle stops 3| may be cast into the lower case section 20 if desired. They are provided to limit'movement of the spindle box 31, in either direction, to some value, such as ten degrees, beyond the regular operating zone, for convenience in handling during shipment and installation. Normally, in operation. the spindle box will not engage stops 3|.

Operation It "will be understood that the adjusting bolt and nut 64, 61 may be adjusted to cause spring pressure from spring (ii to be transmitted directly through to the switchpoints when the hand lever is in either thrown position, which is the preferred adjustment in practice. However, such adjustment of bolt and nut 34. 61 may be made that no spring pressure is transmitted through to the switchpoints when the hand lever is in either thrown position. To facilitate understanding of the functioning of the :switchstand. the operation will first be described with the latter adjustment.

To operate theswi'tchstan'd manually, the hand lever I2 :is raised from one horizontal position and thrown to the opposite horizontal position as will be understood by those skilled in the art. This movement from Fig. :2 position to Fig. 4 position rotates the crank and spring assembly as a unit about its horizontal axis, spring base 42 rotating "in case bearing 26 and pivot link 43 rotating in thrust bushing M. This causes intermediate link 44 and rear link 45 to describe generally conical surfaces, intermediate link 44 rotating 'in spindle block 5-! and the latter sliding in spindle box 31. This moves the spindle box .31 through approximately an angle of thus moving the switchpdints from one closed position, withadjacentswitohpoint against the adjacent "stock rail, to the other closed position, withremote switchpoint againstthe remote stock rail. Figures "6 and "lillustrate the mid-position of the horizontal crank assembly during a manual operation.

For automatic operation from the Fig. 4 position, the camming or wedging action of the wheel flanges of the train on the switchpoints rotates the spindle box '3! which in turn rotates the intermediate link 44 about the axes of pivot pins '52, 53, straightening out the links 44 and 45 and compressing the togglespring 6|, through the dead center position shownin Fig. 5, causing the links 44and 45 to take corresponding positions indicatedlby dot-antledas'h lines V and'W in Fig. 4 on the opposite side of dead center position. This automatic movement does not cause any movement of the hand lever l2.

To throw the switch by hand after an automatic operation, the hand lever I2 is rotated from the horizontal position in Fig. 4 to the oppositehorizontal position, the crank arm 45 and crank pin 44 this time moving from positions and .W through an :arc :and describing conical surfaces below the horizontal plane of the horizontal crank assembly as shown by the dot-anddash lines X and Y in Fig. 6. In other words,

with this type of switchstand there is no fixed :corresponding relationship between the horizontal position of the hand lever and the position of the switchpoints.

As stated above, the adjusting bolt and nut .64, '61 are preferably adjusted in practice to spindle block '51, spindle box 31, spindle 33, crank I3, connecting rod I 4 to the switchpoints. This adjustment has the advantage of insuring always sufficient pressure of the switchpoints against stock rails in either position of the switch; it also assists in operating the switchstand manually.

With the above-mentioned adjustment, 1. e. with the spring transmitting pressure to the switchpoints, when the switch is thrown manually from the Fig. 2 position to the Fig. 4 position, the first part of the lifting movement of the hand lever I2 is aided by the spring 6 I, which lessens the tension on the spring until the spring pressure is taken up by the bolt and nut 64, 61,

after which the movement of the hand lever I2 is free of spring pressure through mid-position (shown in Figs. 6 and '7) until near the other horizontal thrown position (Fig. 4) when s ring pressure is a ain built up on the spring 6 I. Thus the spring assists the switchman in the lifting of the hand lever at the beginning of the manual operation and resists manual o eration toward the end of the throw when it is moving downwardly. Since the upward movement of the hand lever is, ordinarily, more diflicult for the switchman than the downward movement, where the switchman may use his own body weight, the spring has the additional advantage of facilitating hand operation.

As the spring 6| expands at the beginning of the manual operation, crosshead 46 moves towards the spindle 33 and angular relationship between intermediate link 44 and rear link 45 changes slightly; and as the spring 6| contracts at the end of the manual operation, the ori inal relationship of these parts is restored. It will be understood that the assistance derived from the spring in raising the hand lever acts only through a small angle and is not sufflcient in itself to raise the hand lever when the latter is not latched down.

It will be noted that the off-center spindle box 31 constitutes in effect a crank arm and that the H-shaped intermediate link 44 constitutes a crank pin; similarly, the rear link 45 constitutes a crank arm while the crosshead 4'5 and spring base 42 constitutes a crank shaft; and that the movement of the crank pin working in the spindle box 31, due to rotation of the crank shaft during manual operation of the switchstand, causes rotation of the vertical spindle.

The axes of pivot link 43, intermediate link 44 and their connecting pivot pin 52 intersect in a common point, which, when the parts. are all centrally located in their seats or bearings. is

located on the axes of both vertical spindle 33 and horizontal crank shaft 42, 46, which intersect at this point. This geometrical relationship is unstable in certain respects due to play and loose fits discussed below. For example, the common point above mentioned may shift with respect to the axes of both the vertical spindle 33' and the horizontal crank shaft 42, 46; and the axis of the crank shaft 42, 46 may shift laterally so as not to intersect the axis of the vertical spindle 33.

It will be noted that the several links 4346 of the crank assembly are located in the same plane and that the several pivots 52, 53, 54 connecting these links have their axes perpendicular to this plane. Thus the over-centering movement of these links, compressing the spring 6| due to automatic operation, takes place wholly within this plane which is substantially horizontal when the hand lever i2 is in either of the horizontal closed positions.

It will be noted that the fit of the journals 35, 36 of the vertical spindle 33 in their casing bearings 21, 28 constitutes the usual bearing fit, there being no substantial play between these bearings and journals. On the other hand, the pivot link 43 has substantial angular play in its conical seat 5 I; the thrust bushing 4| and spring base 42 have substantial lateral play in their respective casing recesses; the sliding fit of spring cap 58 in the casing is loose, and the sliding fit of crosshead 46 in bore 55 is loose. Such play not only helps increase the instability of the assembly during automatic operation, but minimizes the need for machine fits.

The parts having such loose fits are illustrated in the drawing as being centrally disposed for convenience of illustration even though in practice the operating stresses will cause parts to shift and take ofi-center positions.

During automatic operation while the assembly is passing through dead center position, the spring thrust is taken by the opposite sides of the casing, thus relieving bearings of the vertical spindle 33. In addition, the adjusting bolt and nut 64, 6! relieve spring thrust against the casing during the intermediate part of the manual throw from one horizontal position to the other.

The adjustable bolt and nut facilitates assembly of the spring in the switchstand. The crank toggle arrangement permits automatic operation without corresponding movement of the hand lever and consequent danger of hitting the attendant. At the same time the vertical spindle carrying the target indicates the true position of the switch at all times.

Thus a switchstand has been provided which may be operated either by hand or automatically by a train, in the latter case without disturbing the hand lever. The spring may be adjusted to provide desired pressure of switchpoints against stock rails and to assist the initial raising of the hand lever. The switchstand is of great sensitivity when in dead center position, this sensitivity being caused both by the relief of the vertical sired dead center instability. The convenient adjustment of spring pressure and spring movement merely by removing the handle facilitates adjustment .as well as assembly and disassembly, both in field and shop.

ewes-ps7 While certain novel features of "the invention 'have been disclosed herein, and are pointed .out inxthe annexedclaims, it .will be understood .that various omissions, substitutionsand changes may :be made by those skilled in the-art without departing from the spirit .of the invention.

What isclaimed is:

1. In an automatic switchstand, a case, aspin- :dle 'journaled in said case for connection with a switch, said spindle having a bearing, 'a crank assembly comprising pivoted links and working in said bearing to rotate said spindle by rotation of said crank assembly, spring means for resisting the alignment of said'links during automatic operation, and means for relieving'pressure of said spring means on said spindle at dead center position; and means to rotate said crank assembly to operate the switchstand.

'2. In an automatic switchstand, a case, a spindle journaled in said case for connection to a switch, a crank assembly journaled in said case and comprising an intermediate link'having bearing relation with said spindle, a pivot link pivotally connected to said intermediate link, a rear link pivotally connected to said intermediate link, a crank shaft pivotally connected to said rear link, a yieldable device forming part of the crank assembly for resisting axial movement of said rear link, a support on which said pivot link is pivotally mounted, and thrust means including said pivot link support for withstanding the end thrust of said yieldable device; and means for operating the switchstand by rotating said crank shaft, said intermediate link and rear link passing through a position of substantial alignment for automatic operation, said bearing relation being such that said yieldable device imparts no end thrust to said spindle when said intermediate links and rear link are in substantial alignment.

3. In an automatic switchstand, a case, a spindle journaled in said case for connection to a switch, a crank assembly journaled in said case, said crank assembly comprising the following elements all rotatable as a unit: a link having bearing relation with said spindle, a rear link pivoted to the outer end of said first link, a crosshead pivoted to one of said links, a spring support having a way on which said crosshead is slidable, a spring operative between said crosshead and said support, adjustable devices on said support accessible from the outside of said case for limiting the expansion of said spring; and an operating lever secured to one of said links to rotate said assembly, said links passing thru a position of substantial alignment for automatic op- A eration.

4. In an automatic switchstand, a housing, a vertical spindle journaled in said housing for connection to a switch, a horizontal crank assembly journaled in said housing, said crank assembly comprising the following elements all rotatable as a unit: a link having bearing relation with said spindle, a rear link pivoted to the outer end of said first link, a crosshead pivoted to said rear link, a spring base having a way on which said crosshead is slidable but not rotatable, a spring surrounding said base and operative between said crosshead and said base, adjustable devices on said base accessible from the outside for limiting the expansion of said spring; and an operating leversecured to saidbase, said linkspassing thru a position of substantial alignment for automaticoperation.

5. In an automatic switchstand, ,a'housing, a

spindle journaled in said'housin for connection with the switch, .a crank assembly-comprising a spring base journaled in said case, said spring ,b'ase having a crosshead bore, a crosshead slid iable axially insaid bore but not 'rotatively with respect'to said bore, spring-means acting between :said spring base and said crosshead, 1a :pivoted linkage connected to said crosshead and coop- ;erating with said vertical spindle, a hand :lever edetachably connected to said spring base, threaded adjusting -means, connected to said Lcrosshead and having a non-circular part;fitting :in a non-circular part on said hand lever.

V 16. In an automaticswitchstand, a :housing, a vertical spindle journaled insaid' housing .forcon- .nection withgthe-switch, a horizontal crank-as- :sembly comprising a spring base journaled in said case, said spring base having a :crosshead :bore, -a crosshead slidable axially insaidbore-but .not rotatively with respect to said "bore, spring ,means'acting between said spring base and crosshead, a pivoted linkage connected to :said :crossheadand cooperating with said'verticalspinidle, said spring 'base :having a wrench bore-separated from-said crosshead how by -a wall, a hand ,lever-detachably connected to said spring base. threaded means connected to said crosshead and passing throughsaid wall into-said wrenchbore, a sleeve wrench embracing said threaded means and disposed in said wrench bore and having a non-circular part fitting in a non-circular part on saidhand-lever.

57. In an automatic switchstand, .a housing, ,a spindle journaled in said housing for connection with "the switch, a :crank assembly comprising -a spring :base -jour-naled in said case, said spring .base having a crosshead bore, a crosshead slidable .axially in said bore but not irotatively with respect to saidbore, spring means-actingbetween said spring base and said crosshead, :a pivoted linkage rconnected to said crosshead and coopeerating withnsaid vertical spindle, said spring [base having a wrench .bore separated from said crosshead bore by a wall, a .hand lever bolted to said spring .base, .an adjusting bolt having its headdisposed between the legs of said crosshead .and passing .throughsaid wall into .said wrench .bore,.a ,nut onsaid .bolt, .a sleeve wrench embracing-said nut and disposed in said Wrench bore and having a non-circular boss .fitting in .a corr sponding hole in said hand lever.

,8. In an.automatic switchstand, a housing, a spindlejournaled in saidhousing for connection .with a. switch, a crank assembly having a horizontal axisof rotation journaled in said housing, said assembly comprising a spring base journaled in said housing, a crosshead axially slidable, but non-rotatable, relative to said spring base, said spindle carrying an off-center open .boX, a spindle block slidable in .said box, an intermediate link vjournaled in said block, a rear link, a v.pivot connecting said rear link and crosshead, asepond pivot connecting said rear link and intermediate link, a pivot link, a third pivotconnecting said pivot link and intermediate link, a spring operating between said crosshead and springrbase, and a thrust bushing having a socket seated in said case oppositesaid spring base and journaling said pivot link to take the stress of said spring at dead center position when the switchstand is automatically operated; .and. anoperating member secured to said spring base to rotate said crank assembly.

9. an automatic switchstand, a housing, a spindle journaled insaid housing for connection with a switch, a ,crank assembly having .a ,horizontal axis of rotation journaled in said housing, said assembly comprising a spring base journaled in said housing, a crosshead axially slidable, but non-rotatable, relative to said spring base, said spindle carrying an off-center open box, a spindle block slidable in said box, an intermediate link journaled in said block, a rear link, a pivot'connecting said rear link and crosshead, a second pivot connecting said rear link and intermediate link, a pivot link, a third pivot connecting said pivot link and intermediate link, a helical spring concentrically mounted on said spring base and operating between said crosshead and spring base, and a thrust bushing having a conical bore seated in said case opposite said spring base and journaling said pivot link to take the stress of said spring at dead center position when the switchstand is automatically operated; and an operating member secured to said spring base to rotate said crank assembly.

10. In a switchstand, a case, a vertical spindle journaled in said case for connection with a switch, said spindle having an off-center box, said case having bearings in its opposite side walls, a crank assembly for operating said spindle, said assembly comprising a thrust bushing in one of said bearings, said thrust bushing having a conical bore with a recess in its bottom, a ball in said recess, a pivot link disposed in said bore and having a recess engaging said ball, a spindle block slidable in said box and having a cylindrical bore, an H-shaped cylindrical inter mediate link journaled in said spindle block bore, a spring base comprising a reduced journal portion seated in said other bearing and a flange and a non-circular bore, a U-shaped crosshead slidable in said non-circular bore, a spring cap connected to said crosshead, a helical spring surrounding said crosshead and spring base and disposed between said spring cap and base flange, a rear link disposed between adjacent legs of said intermediate link and the legs of said crosshead, said pivot link being disposed between adjacent legs of said intermediate link, a pivot pin connecting said pivot link and intermediate link, a second pivot pin connecting said intermediate link and rear link, a third pivot pin connecting said rear link and crosshead, and a hand lever bolted to said spring base.

11. In a switchstand, a case, a vertical spindle journaled in said case for connection with a switch, said spindle having an off-center box, said case having openings in its opposite side walls, a crank assembly for operating said spindle, said assembly comprising a thrust bushing disposed in one of said openings, said thrust bushing having a bore, a pivot link disposed in said bore, a spindle block slidable in said box and having a cylindrical bore, a cylindrical intermediate link journaled in said spindle block bore, a spring base comprising a reduced journal portion seated in said other case opening and a flange and a non-circular bore, a crosshead slidable in said non-circular bore, a spring cap connected to said crosshead, a helical spring surrounding said crosshead and spring base and disposed between said spring cap and base flange, a rear link, a pivot pin connecting said pivot link and intermediate link, a second pivot pin connecting said intermediate link and rear link, a third pivot pin connecting said rear link and crosshead, a hand lever bolted to said spring base, said spring base having a wrench bore, an adjusting bolt having its head disposed between the legs of said crosshead and passing through a wall into said wrench bore, a nut on said bolt, a sleeve wrench embracing said nut and disposed in said wrench bore and having a noncircular part fitting a non-circular part on said hand lever.

12. In an automatic switchstand. a case, a spindle journaled in said case for connection to a switch, said spindle having an off-center, openended box forming a crank, a crank assembly comprising an intermediate link passing through said box, a link pivotally seated in said case and pivoted to the inner end of said intermediate link, a rear link having one end pivoted to the outer end of said intermediate link, a crank shaft journaled in said case and pivoted to the other end of said rear link, means including a spring surrounding said crank shaft for exerting an end thrust between said rear link and said case; said spring allowing said crank assembly to pass through a position, with all said links and crank shaft in substantial alignment, for automatic operation; and a lever connected to said crank shaft to rotate said crank assembly for manual operation, said intermediate link imparting no end thrust to said box when said links and crank shaft are in substantial alignment.

13. In an automatic switchstand, a case, a spindle journaled in said case for connection to a switch, said spindle having an opening extending laterally therethrough, a crank assembly journaled in said case and comprising a crank pin element disposed in said spindle opening, a crank shaft element, and a crank arm element pivotally connected between the aforementioned elements, means for tensioning said crank assembly to yieldably resist aligning of said elements during automatic operation, means applied to the remote ends of said crank pin element and of said crank arm element for resisting end thrust due to said tensioning and thereby to relieve said spindle of pressure due to said tensioning means when the switchstand is in dead center position, and means for rotating said crank shaft element to operate the switchstand for manual operation.

14. In an automatic switchstand, a case having bearings, a spindle journaled in said case bearings for connection with a switch, a crank assembly comprising a chain of pivoted links provided with means interengaging with said spindle to rotate said spindle by rotation of said crank assembly, spring means for tensioning said crank assembly for yieldably resisting alignment of said links to permit automatic operation, said chain comprising at least three links which assume positions in substantial alignment in dead center position, and pivotal mountings for the remote ends of the end links of said chain; means supporting said mountings for transmitting the end thrust of said links to the case independently of said case spindle bearings, and means to rotate said crank assembly to operate the switchstand.

ALFRED F. ANDERSEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 357,475 Foreman Feb. 8, 1887 1,373,031 Strom et al Mar. 29, 1921 1,677,388 Gray July 17, 1928 2,054,543 Hofiman et al. Sept. 15, 1936 

